BARREL 3A Ephemeris (EPHM) Geographic and Magnetic Coordinates, Level 2, 4 s Data

Geographic and Magnetic Coordinates: The ephemeris data products, which include the balloon epoch time, latitude, longitude, and altitude, are each returned from the payload once every 4s. Geographic coordinates are obtained from an onboard Global Positioning System, GPS, unit. Magnetic coordinates are derived by using the International Radiation Belt Environment Modeling, IRBEM, FORTRAN library.

地理与地磁坐标：本数据集所包含的星历数据产品涵盖气球历元时间、纬度、经度及海拔高度，所有数据均由有效载荷每4秒回传一次。其中地理坐标由机载全球定位系统（Global Positioning System，GPS）获取；地磁坐标则通过国际辐射带环境建模（International Radiation Belt Environment Modeling，IRBEM）FORTRAN程序库推导得到。